The present invention relates to a surgical instrument, and in particular to an impactor for use with orthopaedic implants.
Impactors are used during orthopaedic arthroplasty procedures to drive the implant components onto the bone. Often bone cement is also used to secure the implant to the bone, but there is usually a tight or interference fit between the implant component. Hence, a tool, such as a mallet, hammer or similar, is used to drive the implant component onto the bone, by hitting a free end of the impactor, while the impactor engages the implant. However, it is important to ensure that an even pressure is applied to the component, so that it seats correctly on the resected bone surface, and also that the bearing surfaces are not damaged during impaction. Hence, different impactors can be needed in order to impact the same or different implant components, so that they are correctly seated and damage is avoided.
Impactors are used during orthopaedic arthroplasty procedures to drive the implant components onto the bone. Often bone cement is also used to secure the implant to the bone, but there is usually a tight or interference fit between the implant component. Hence, a tool, such as a mallet, hammer or similar, is used to drive the implant component onto the bone, by hitting a free end of the impactor, while the impactor engages the implant. However, it is important to ensure that an even pressure is applied to the component, so that it seats correctly on the resected bone surface, and also that the bearing surfaces are not damaged during impaction. Hence, different impactors can be needed in order to impact the same or different implant components, so that they are correctly seated and damage is avoided.
For example, an impactor exists which has a handle and a plurality of releasably attachable head parts. The head parts and the handle have an attachment mechanism which allows the heads to be interchanged on the handle. A head configured to impact a femoral component of an artificial knee joint can be provided, together with a headed configured to operate on the notch of the femoral component and also a head configured to operate on a tibial component. However, use of such an impactor can cause delays in the surgical procedure as it is necessary to swap the heads. Also, such devices are more complex to manufacture and use and can be difficult to sterilise owing to the mechanical attachment mechanism for the different heads.
Also, some of impactor heads can be attached to the implants, but then tend to be useable only with a specific implant and again are more complex to manufacture and harder to sterilise.
More simple impaction devices are also available which can be used generally for impaction but do not have any inbuilt features to perform the specific impaction tasks required. This can lead to damage of the implant components due to scratching of the bearing surfaces and/or deformations and hence have limited utility.
Hence, there is a need for a multifunction impactor which can more easily be used to reliably impact orthopaedic implants.